Preheat oven to 375°F. Run to close the windows and to turn on both air conditioners.

Lightly oil an 8- or 9-inch springform pan, then dust the pan with flour, tapping out excess.

In a large bowl, whisk together the spelt flour, almond meal, baking powder, and salt. In a smaller bowl, whisk the oil, egg, half-and-half, lemon juice and zest, the 2/3 cup sugar, and the almond extract, blending thoroughly. Add the wet ingredients to the dry, saying a few words to bless their union.

Pour the batter into the prepared pan. Arrange the plum halves, cut side down, on top of the batter in a concentric circle (or some other design with different radii).

In a little bowl, combine the almonds, the 2 Tbsp. sugar, and the butter, mixing with your fingertips until combined enough to break into blobs with which to dot the top of the cake.

Bake the cake until the topping is golden brown and a tester inserted in the center of the cake comes out clean, about 45 minutes. Transfer the pan to a wire rack and let cool for 20 minutes. Then flop on the bed in front of the air conditioning to do the same.

Remove the outer ring from the springform pan and place the cake on a serving platter. Cut into the size slices that you deem appropriate, but don't dare pair it with a small scoop of pistachio or almond or ricotta gelato. Do attempt to save a slice or two to have at room temperature the next, er, morning, as it only improves with a good night's sleep--and a cup of strong coffee.